Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Some Mathematical Expressions

We will discuss the solutions of Eqs. (16.1-16.3) by solving the differential equations with the additional constraint that + + j = 1. Here we will analyze steady-state results. In Section 16.5, we will analyze the consequences of product formation using transient solutions. [Pg.560]

We will analyze in detail in Section 16.2.2 the rates of product formation and CO consumption as a function of the rate parameters of Eqs. (16.1-16.3). We will solve these equations assuming that the rate parameters are independent of the chain length. In this case, the ratio of will be independent of the chain [Pg.560]

As a consequence of the rate parameters being independent of chain length, a = is independent of the chain length, and we find the following relation [Pg.560]

This quadratic expression in a results because of the incorporation of reversible C-C bond formation in the equations. The solution for a is readily found  [Pg.560]

One notes the rapid convergence of a to the infinite hydrocarbon chain value. When we discuss the microkinetics simulations, we will return to this point. [Pg.560]


This appendix includes some mathematical expressions that are used in this text. It is not intended to be comprehensive or to substitute for a mathematics textbook. [Pg.393]

Several models have been suggested to simulate the behavior inside a reactor [53, 71, 72]. Accordingly, homogeneous flow models, which are the subject of this chapter, may be classified into (1) velocity profile model, for a reactor whose velocity profile is rather simple and describable by some mathematical expression, (2) dispersion model, which draws analogy between mixing and diffusion processes, and (3) compartmental model, which consists of a series of perfectly-mixed reactors, plug-flow reactors, dead water elements as well as recycle streams, by pass and cross flow etc., in order to describe a non-ideal flow reactor. [Pg.334]

This chapter is written with three objectives in mind. First, the importance of the size and concentration of the particles to be treated in determining the eflFectiveness of some solid-liquid separation processes is evaluated. Second, past theories are used to examine how particle sizes and concentrations are altered by these treatments. Third, interrelationships among the individual unit processes that comprise a complete treatment system are investigated to provide a base for an integral treatment plant design. These aims are undertaken using a typical water treatment system as employed in practice to remove turbidity from surface water supplies. Before addressing these objectives, it is useful to review some mathematical expressions of particle size distributions, and to identify some important properties of these functions. [Pg.354]

Options) but language in menus and dialog boxes (top scrolling list Menus and dialogs) and also some mathematical expressions (top scrolling list Math language). Earlier versions (8-11) Mathcad have only British and American dialects in spell checking. [Pg.240]

Transactions that rely on geographically distributed parameters of the event, such as ground motions, have also appeared in the market in the form of second-generation parametric indices. These indices are computed as a weighted sum of some mathematical expression, often... [Pg.764]

Finally, in order to proceed we need to adopt some mathematical expression for the molar excess Gibbs energy. There are several models available in the literature (Reid et al., 1987) describing g, and all of them contain adjustable parameters whose best fitting values are... [Pg.460]

Here a suitable equation of state is required to provide a mathematical expression for the mixture molar volume, V. For some equations of state, it is better to use a form of equation 28 in which the integral is volume expHcit (3). Note also that for an ideal gas — Z — 1, and 0 = 1. [Pg.236]

The following details mathematical expressions for instantaneous (point or local) or overall (integral) selectivity in series and parallel reactions at constant density and isotliermal conditions. An instantaneous selectivity is defined as the ratio of the rate of formation of one product relative to the rate of formation of another product at any point in the system. The overall selectivity is the ratio of the amount of one product formed to the amount of some other product formed in the same period of time. [Pg.355]

In order to obtain a specific mathematical expression for the wave packet, we need to select some form for the function A k). In our first example we choose A(k) to be the gaussian function... [Pg.10]

In Section 3.1 the mathematical expressions that result from integration of various reaction rate functions were discussed in some detail. Our present problem is the converse of that considered earlier (i.e., given data on the concentra-... [Pg.40]

The mathematical expression of N(6, q>, i//) is complex but, fortunately, it can be simplified for systems displaying some symmetry. Two levels of symmetry have to be considered. The first is relative to the statistical distribution of structural units orientation. For example, if the distribution is centrosymmetric, all the D(mn coefficients are equal to 0 for odd ( values. Since this is almost always the case, only u(mn coefficients with even t will be considered herein. In addition, if the (X, Y), (Y, Z), and (X, Z) planes are all statistical symmetry elements, m should also be even otherwise = 0 [1]. In this chapter, biaxial and uniaxial statistical symmetries are more specifically considered. The second type of symmetry is inherent to the structural unit itself. For example, the structural units may have an orthorhombic symmetry (point group symmetry D2) which requires that n is even otherwise <>tmn = 0 [1], In this theoretical section, we will detail the equations of orientation for structural units that exhibit a cylindrical symmetry (cigar-like or rod-like), i.e., with no preferred orientation around the Oz-axis. In this case, the ODF is independent of t/z, leading to n — 0. More complex cases have been treated elsewhere [1,4]... [Pg.299]

Recently, Orosz et al. [136] reviewed and critically reevaluated some of the known mechanistic studies. Detailed mathematical expressions for rate constants were presented, and these are used to derive relationships, which can then be used as guidelines in the optimization procedure of the POCL response. A model based on the time-window concept, which assumes that only a fraction of the exponential light emission curve is captured and integrated by the detector, was presented. Existing data were used to simulate the detector response for different reagent concentrations and flow rates. [Pg.147]

Binary solutions have been extensively studied in the last century and a whole range of different analytical models for the molar Gibbs energy of mixing have evolved in the literature. Some of these expressions are based on statistical mechanics, as we will show in Chapter 9. However, in situations where the intention is to find mathematical expressions that are easy to handle, that reproduce experimental data and that are easily incorporated in computations, polynomial expressions obviously have an advantage. [Pg.73]

We define the linear growth rate Vg as the linear velocity of displacement of a crystal face relative to some fixed point in the crystal. vg may be known as a function of c and c , derived from the theory of transport control, and as a function of c and cs as well, derived from the theory of surface control. Then c may be eliminated by equating the two mathematical expressions... [Pg.601]

If you do look up apparent volumes of distribution for different drugs you will find some which are remarkably high, and you may have difficulty understanding how that can be. Again it is important to remember that apparent Vd is not a real measured volume, but a mathematical expression. [Pg.134]

We attempt here to develop a mathematical expression for the dependence of the dilute solution intrinsic viscosity of multispecies polymers on both molecular weight and polymer composition with some broad degree of generality and to particularize the result for the specific cases of copolymers and terpolymers such as SAN and S/MA/MM. The details of the derivation are specific to polymers resulting from addition polymerization across a single double bond in each monomer unit. In principle the approach may be expanded to other schemes of polymerization so long as... [Pg.264]

Since the mathematical expression for < u2) is equivalent to that for , measurements of should provide information which can be utilized to check the theory of , e.g. Eq. (C-3), for polypeptides in the helix-coil transition region. This idea, however, cannot be developed in straightforward fashion because there is no available theory to estimate of interrupted helical polypeptides from dielectric dispersion curves. Therefore, we are forced to proceed on some yet unproven assumptions, or even drastic approximations. [Pg.133]

Some mathematical manipulations convert AGm into an expression for jx, — am°, which is directly related to 7r through Equation (21). [Pg.121]

A general mathematical expression has been derived to estimate standard errors 5(y) in the predicted concentrations, based on the Errors in Variables (EIV) theory [62], which, after some simplifications, reduces to the following equation [63] ... [Pg.227]

The major focus in the discussions below is on the chemical nature of the enzymatic catalysts and coenzymes used in the initial transformation step. We will also pay some attention to the details of these enzymatic mechanisms. This will provide a basis for understanding how mathematical expressions describing the associated transformation rates can be derived when enzyme-catalyzed reactions limit the overall biotransformation rate (i.e., steps 2, 3 or 4 shown in Fig. 17.1). [Pg.706]


See other pages where Some Mathematical Expressions is mentioned: [Pg.7]    [Pg.6]    [Pg.522]    [Pg.559]    [Pg.7]    [Pg.6]    [Pg.522]    [Pg.559]    [Pg.111]    [Pg.145]    [Pg.531]    [Pg.445]    [Pg.111]    [Pg.46]    [Pg.13]    [Pg.105]    [Pg.13]    [Pg.67]    [Pg.566]    [Pg.138]    [Pg.27]    [Pg.718]    [Pg.52]    [Pg.53]    [Pg.113]    [Pg.37]    [Pg.350]    [Pg.319]    [Pg.420]    [Pg.113]    [Pg.491]    [Pg.209]    [Pg.7]    [Pg.702]   


SEARCH



© 2024 chempedia.info